1. Field of the Invention
The invention relates to the treatment of hydrated biological materials, and more precisely to the field of the extraction of juices and flavors from various plant substrates such as fruits, vegetables or other leaves. It relates in particular to a plant in which there is no need to add exogenous water in order to heat or blanch said materials.
2. Description of the Prior Art
In the Applicant's document FR-A-2 656 547 a continuous apparatus was provided for deaerating, heating, maintaining at temperature and cooling under vacuum solid organic materials. This plant chiefly comprises a heating chamber into which steam is injected at high temperature to produce the heating of the material to be treated. This heated material is subsequently transferred to a decompression chamber in which a pressure lower than 0.1 bar prevails and where the vaporization of the water present within the material to be treated takes place. A solid material is thus obtained which is lighter and suited to being treated either by pressurizing or by another means of conditioning. This plant gives full satisfaction but has the disadvantge of requiring the injection of exogenous steam in order to heat the material to be treated. This addition of steam entails a phenomenon of dilution of the material to be treated, which dilution must be compensated by an additional concentration stage. The need for a concentrating device makes the plant more complicated as a whole and reduces the economic advantage of this plant. Furthermore, the addition of exogenous steam is generally prohibited, especially in viticulture or for obtaining fruit juice known as "pure juice".
A plant relating more particularly to the treatment of perfumed and condimental plants requiring a number of extractions was proposed in document FR 2 638 333. This plant enables a number of extractions to be carried out on the same substrate with a single set of equipment, but has the disadvantage of operating noncontinuously, and above all, of requiring an exogenous steam source.